Hi all , so I asked the other day how to wipe cache partition on UI 3.0 on my S10 as pressing the volume up Bixby and power buttons didn't work with phone off , this is what you need to do to wipe cache partition .
Power off the phone
Plug your data/charger cable in the usb c socket on your phone
Plug the other end in to a laptop / tablet / headphones .
Press volume up Bixby and power buttons until the android man appears .
Release buttons and then select what you want to do 👍🏻
Hope this helps .